Genomic Signatures of Selection in the Modern Horse

Abstract Text: We are using genome-wide genotype data to identify segments that have undergone selection during breed formation.  One region encompasses the GYS1 gene, where a gain of function mutation shows historical evidence of positive selection in draft horses, but is now associated with exercise intolerance.  Another region contains the MSTN gene where a haplotype containing several variants is present in 93% of Quarter Horses and 50% of Thoroughbreds, and is associated with altered muscle fiber type proportions. A third region contains the DMRT3 gene where a mutation permissive to performing alternative gaits in many breeds has been found.  Lastly, conserved haplotypes underlying signals of selection in the draft breeds and Miniature horse suggest the presence of a locus important in the determination of size.  These are some of the first steps towards the identification of genes important in the specialization of modern horse breeds.

Keywords: Domestic Horses, F_ST, Haplotypes